Ultrasound probe and method of manufacturing ultrasound probe

Abstract

Provided are an ultrasound probe including high-sensitive piezoelectric elements and a method of manufacturing an ultrasound probe. The ultrasound probe includes a plurality of piezoelectric elements on a backing material arranged in an array along an arrangement direction. Each of the plurality of piezoelectric elements includes a laminate in which a first conductive part, a piezoelectric body part, and a second conductive part are laminated on a surface of the backing material in order. A plurality of acoustic matching part respectively arranged on the second conductive parts of the plurality of piezoelectric elements is provided. A plurality of third conductive parts acquired by respectively joining a part of the plurality of acoustic matching parts in an elevation direction to the second conductive parts of the plurality of piezoelectric elements is provided. A fourth conductive part that electrically connects the plurality of third conductive parts to each other is provided. The second conductive parts of the plurality of piezoelectric elements, the plurality of third conductive parts, and the fourth conductive part form a common electrode common to the plurality of piezoelectric elements.

What is claimed is: 
     
       1. An ultrasound probe comprising:
 a plurality of piezoelectric elements on a backing material arranged in an array along an arrangement direction, 
 wherein each of the plurality of piezoelectric elements includes a laminate in which a first conductive part, a piezoelectric body part, and a second conductive part are laminated on a surface of the backing material in order, 
 a plurality of acoustic matching parts respectively arranged on the second conductive parts of the plurality of piezoelectric elements is provided, 
 a plurality of third conductive parts acquired by respectively joining a part of the plurality of acoustic matching parts in an elevation direction to the second conductive parts of the plurality of piezoelectric elements is provided, 
 a fourth conductive part that electrically connects the plurality of third conductive parts to each other is provided, and 
 the second conductive parts of the plurality of piezoelectric elements, the plurality of third conductive parts, and the fourth conductive part form a common electrode common to the plurality of piezoelectric elements. 
 
     
     
       2. The ultrasound probe according to  claim 1 ,
 wherein the plurality of third conductive parts and the fourth conductive part form a commonization conductive part which spreads over the plurality of piezoelectric elements and has a single-layer structure in a lamination direction of the laminates. 
 
     
     
       3. The ultrasound probe according to  claim 2 ,
 wherein the fourth conductive part is constituted by a plurality of conductive fillers filling between the plurality of third conductive parts in the arrangement direction. 
 
     
     
       4. The ultrasound probe according to  claim 2 ,
 wherein the fourth conductive part extends in the arrangement direction over the plurality of piezoelectric elements, and is joined to side surfaces of the plurality of third conductive parts in the elevation direction. 
 
     
     
       5. The ultrasound probe according to  claim 1 ,
 wherein the plurality of third conductive parts and the fourth conductive part form a commonization conductive part which spreads over the plurality of piezoelectric elements and has a structure in which a plurality of layers is laminated in the lamination direction of the laminates. 
 
     
     
       6. The ultrasound probe according to  claim 5 ,
 wherein the fourth conductive part extends in the arrangement direction over the plurality of piezoelectric elements, and is joined to surface of the plurality of third conductive parts in the lamination direction of the laminates. 
 
     
     
       7. The ultrasound probe according to  claim 6 ,
 wherein each of the plurality of third conductive parts includes a cut-out part cut such that a wall part protruding in the lamination direction of the laminates is formed at an end portion in the elevation direction, and 
 the fourth conductive part is arranged on the cut-out parts of the plurality of third conductive parts. 
 
     
     
       8. The ultrasound probe according to  claim 6 ,
 wherein each of the plurality of third conductive parts includes a groove extending in the arrangement direction, and 
 the fourth conductive part is arranged within the grooves of the plurality of third conductive parts. 
 
     
     
       9. The ultrasound probe according to  claim 6 ,
 wherein the fourth conductive part has a lamination structure in which a plurality of layers is laminated in the lamination direction of the laminates. 
 
     
     
       10. The ultrasound probe according to  claim 6 ,
 wherein the third conductive part has an acoustic impedance higher than an acoustic impedance of the fourth conductive part. 
 
     
     
       11. The ultrasound probe according to  claim 6 ,
 wherein, in the lamination direction of the laminates, a thickness of the third conductive part has a value of substantially ¼ of a wavelength of here an ultrasound propagating through the third conductive part, and a thickness of the fourth conductive part has a value of substantially ¼ of a wavelength of the ultrasound propagating through the fourth conductive part, the ultrasound having a resonance frequency of the piezoelectric body part. 
 
     
     
       12. The ultrasound probe according to  claim 2 ,
 wherein, in the lamination direction of the laminates, a thickness of the commonization conductive part has a value of substantially ¼ of an average wavelength of an ultrasound propagating through the commonization conductive part, the ultrasound having a resonance frequency of the piezoelectric body part. 
 
     
     
       13. The ultrasound probe according to  claim 2 ,
 wherein the third conductive part has a lamination structure in which a plurality of layers is laminated in the lamination direction of the laminates. 
 
     
     
       14. The ultrasound probe according to  claim 2 ,
 wherein an insulation part is further arranged on the commonization conductive part so as to correspond to the plurality of piezoelectric elements, and 
 the insulation part has an acoustic impedance lower than an acoustic impedance of the commonization conductive part. 
 
     
     
       15. The ultrasound probe according to  claim 14 ,
 wherein, in the lamination direction of the laminates, each of a thickness of the commonization conductive part and a thickness of the insulation part has a value of substantially ¼ of an average wavelength of an ultrasound propagating through the commonization conductive part, the ultrasound having a resonance frequency of the piezoelectric body part. 
 
     
     
       16. The ultrasound probe according to  claim 2 ,
 wherein commonization conductive parts are respectively arranged at both end portions of the second conductive part of each of the plurality of piezoelectric elements in the elevation direction. 
 
     
     
       17. The ultrasound probe according to  claim 16 ,
 wherein the commonization conductive parts respectively arranged on both the end portions of the second conductive part of each of the plurality of piezoelectric elements in the elevation direction have sizes equal to each other and acoustic impedances equal to each other. 
 
     
     
       18. The ultrasound probe according to  claim 2 ,
 wherein, in the lamination direction of the laminates, a thickness of the commonization conductive part and a thickness of a portion of the acoustic matching part other than the third conductive part have values which are substantially equal to each other. 
 
     
     
       19. A method of manufacturing an ultrasound probe including a plurality of piezoelectric elements on a backing material arranged in an array along an arrangement direction, the method comprising:
 a first step of laminating a first conductive layer, a piezoelectric body layer, and a second conductive layer on a surface of the backing material in order; 
 a second step of forming an acoustic matching layer and a third conductive layer which extend in the arrangement direction on a surface of the second conductive layer; 
 a third step of forming a plurality of composite laminates separated from each other in the arrangement direction by dicing the first conductive layer, the piezoelectric body layer, the second conductive layer, the acoustic matching layer, and the third conductive layer at a set pitch along a direction crossing a direction in which the third conductive layer extends and in a lamination direction; and 
 a fourth step of forming a fourth conductive part that electrically connects the third conductive layers of the plurality of composite laminates, which are separated from each other, to each other, 
 wherein a common electrode common to the plurality of piezoelectric elements is formed by using the second conductive layers and the third conductive layers of the plurality of composite laminates and the fourth conductive part. 
 
     
     
       20. The method of manufacturing an ultrasound probe according to  claim 19 ,
 wherein the fourth conductive part is formed by filling spaces between the third conductive layers of the plurality of composite laminates in the arrangement direction with conductive fillers. 
 
     
     
       21. The method of manufacturing an ultrasound probe according to  claim 19 ,
 wherein the fourth conductive part extends in the arrangement direction over the plurality of piezoelectric elements, and is joined to the third conductive layers of the plurality of composite laminates. 
 
     
     
       22. The method of manufacturing an ultrasound probe according to  claim 19 , further comprising:
 a step of filling spaces between the plurality of composite laminates with insulating fillers.